Patent GB-559282-A (GB)
Title: Improvements in or relating to automatically reclosing electric circuit breakers
IPC: H01H75/04
Filed: 1942-10-15
Abstract: 559,282. Protective cut-out systems; automatic circuit-breakers ; electromagnetic switches ; friction clutches. WFSTINGHOUSE ELECTRIC INTERNATIONAL CO. Oct. 15, 1942, No. 14470. Convention date, Oct. 17, 1941. [Class 38 (v)] [Also in Group XXIV] An automatically - reclosing circuit - breaker is adapted to be reclosed by an electric motor operating through a clutch such that the reclosure is initiated before the breaker is in the fully-open position, means being provided for operating the clutch to disconnect the motor from the contacts in the event that'the fault persists. The contacts preferably comprise interupting and disconnecting contacts in series, the timing of the reclosure causing the initiation thereof when the interrupting contacts have opened and the arc quenched, but before the disconnecting contacts separate. The breaker proper comprises a liquid-containing tank having one or more seriesconnected contacts in arc-quenching devices 19 attached to each of the lead-in conductors 25, the contacts in each case being connected to a common rod which is urged to open position by a spring such that, as the lift-rod 69 is lowered, these contacts open and the arc is finally quenched before isolating contacts 71 on the cross-bar 21 separate from companion contacts on the rod, Fig. 2. (not shown). The opening force is supplied by a spring 111 rotating shafts 91, 105 and crank 95 counterclockwise, Fig. 1, but in the case of fault-tripping , reclosure begins before the isolating contacts 71 begin to separate, and is effected by. energization of a motor 83 driving shaft 91 through a shaft 89, worm gearing 141, 139, and an electromagnetically-operated clutch for coupling together the shafts 89, 91. Wormwheel 139 is freely rotatable on shaft 91 and carries a member 137 on which is fixed a pin 135 serving as one end anchorage for a clutch band 131, the other end of which is anchored by a pin 143 to one end of a further clutch band 129, the other end of which is fixed to a block 171 formed with a wedge 175 co-operating with a roller 177 on a clutch arm 145. The latter has secured to it by means of a disc spring 159 the armature 157 of an electromagnetic clutch comprising a coil 153 in a housing 155 secured to shaft 91. Normally, rotation of shaft 89 causes wormwheel 139 to rotate clockwise and drive band 131 and, through a spring 167 connected between pins 135, 143, the band 129 which, through a further spring 165 and block 171, causes the arm 145 and armature 157 to rotate freely on the shaft 91. When the clutch coil 153 is energized, the movement of arm 145 is opposed, and wedge 175, compresses both springs 165, 167, tightening both bands 129, 131 about the drum 133 fast on shaft 91, so rotating the latter until the breaker is closed. The motor 83 and clutch 153 are then both de-energized, as later described but a roller 195 in housing 155 is held by a latch 181 pivoted at 183 and in turn latched by a pivoted lever 199 adapted to be knocked up by the adjustable plunger 219 of a trip coil 211. When this happens, a surface 231 on latch 181 is guided on to a part 229 of housing 155 to prevent resetting of both latches until the breaker is reclosed. Contacts 277, Fig. 3, are adapted to be closed by a spring-urged lever 313 which is pivoted at 315 and released by a cam surface 280 on shaft 91 as soon as the breaker begins to open. On overload, the trip relay 243, Fig. 6, closes contacts 247 which energize the trip coil 211 over still-closed contacts 259, and a reclose relay 263 which, at contacts 267, and over now-closed contacts 277, energizes the clutch coil 153 over contacts 305, and also a motor-control relay 269. The latter closes sealing-in contacts 269b and at contacts 269a energizes motor 83 which begins the reclosing operation. If the fault is removed, the breaker is latched in and contacts 277 open and de-energize the clutch and relay 269. Otherwise, the relay 243 again operates and, contacts 259 being now closed and a circuit being also made for a relay 329 which closes contact 333, windings 285, 307 are energized in parallel and, respectively, de-energize the motor-control relay 269 (and hence the motor) and clutch 153, so preventing further attempts at reclosure so that the breaker moves to fullopen position with contacts 71 separated. In this operation, contacts 343 make a retaining circuit for coil 345, which is de-energized to allow the relay contacts 305 to reclose as soon as the breaker clears the fault, but as contacts 267 are also opened, relay 269 is not energized. Reclosure is then effected by manual switch 347 which makes an alternative circuit to contacts 267, but if a fault is present tripping at once occurs by de-energization of the clutch 153. Fig. 7 shows an arrangement for effecting three fractional-stroke reclosures, whereupon a transfer relay 385 changes over to a timing reclose device 418. The trip relay 359 closes at contacts 361a trip coil circuit 211 including contacts 379, and also contacts 361b energize over closed contacts 393 the motor-control relay 383, which seals itself at 383b and at 383a energizes motor 83. A switch 409 operated by the opening breaker energizes clutch 153 so as to reclose the breaker in' the manner described, and if the breaker closes on to a fault, it is at once disconnected by opening of contacts 417a of relay 417 energized by closure of contacts 361a, 379 and in parallel with the trip coil 211. For controlling the fractional-stroke reclosures, a relay 429 is energized while the breaker is closed, and when released makes intermittent contact at 429a to energize a slow-release relay 431 until its vibrations die down, the relay 431 thereby retaining its contacts 431a to energize a set of relays 425, 426, 427 in conjunction with back contacts 433 of the breaker. The arrangement is such that after three such reclosures and trippings, all three relays are energized and their contacts 425b ... 427b in series energize transfer relay 385 which opens contacts 385a in the motor and clutch circuits, closes contacts 385b to connect up reclosing device 418 over contacts 473 of the breaker, and closes contacts 385c to seal itself in when, due to opening of 385d, relays 425... 427 are de-energized and restore. Device 418 is repeatedly energized at longer intervals to close contacts 418a, 418b the latter energizing motorcontrol relay 383 over contacts 489a, 393 whereby the breaker is closed as before. Closure of contacts 493 energizes coil 489 over contacts 418a, and its contacts 489a de-energize the relay 383 and hence the motor and clutch. Relay 489 also has sealing contacts 489b. When the breaker closes, contacts 473 open and device 418 opens its contacts 418a, 418b. If the fault is cleared, 418 resets without again closing its contacts and energizes a relay 481 to open at 481a the circuit of relay 385, but if the fault persists and 473 reclose, a further attempt by 418 is made until the prescribed number is exhausted. A manual switch 501 is then employed to energize relays 383,489.